The Missouri DOT (MoDOT) is experimenting with a potential solution to that costly and deadly problem. As part of a $55 million stimulus-funded project to revamp a stretch of the state's Route 141, the agency is including a special additive in 2,000 feet of concrete pavement. TX Active, manufactured by Essroc, reacts with pollutants from vehicle emissions to capture them, then harnesses the power of sunlight to break the dangerous chemicals into harmless components.

The department's test is inspired by similar, successful tests that occurred in Italy. According to Gates, the European application of the technology showed the additive led to improved air and water quality on the roadway.

After initial testing by MoDOT technicians demonstrated that the “photocatalytic” concrete offered the same durability, strength, and other physical properties as portland cement concrete, managers decided to commit $200,000 to running a larger test. The project began in March 2010, and is expected to wrap up in September 2012.

“Tests in Italy show about a 40% improvement in air and water runoff quality,” says Gates. “Our expectations would be to yield similar results to those. We expect this product will improve the air quality in the locations it is placed.”

Gates points out that the department's test is still in its infancy, and differences in climate, weather patterns, and vehicle volume between Italy and Missouri could bear on the results. Managers, however, are optimistic about the end result. And although the high-tech formulation costs about 10 times more than traditional pavement, the improved quality of life could make the investment worthwhile.

The American Lung Association's “2010 State of the Air Report" reveals the country's dirtiest areas. Based on U.S. EPA's Air Quality System database, the report looks at the concentration of key pollutants over extended time periods. For a list of the country's dirtiest areas, and to see how your community measures up, click here.